Fixes #291
Add option to automatically size dropdown width
Use $.prop() to get "multiple" attribute

The string 
opts.element.attr("multiple") 
returns:
1) string "multiple" - if element have attribute multiple (<select name="..." multiple></select>)
2) undefined - if element have not attribute multiple (<select name="..."></select>)
It is written in the documentation:
"As of jQuery 1.6, the .attr() method returns undefined for attributes that have not been set."
"To retrieve and change DOM properties, use the .prop() method."
(http://api.jquery.com/attr/)

I am propose use "prop" function. The string
opts.element.prop("multiple")
returns:
1) boolean "true" - if element have attribute multiple
2) boolean "false" - if element have not attribute multiple

After, the "multiple" variable use in check of the condition:
select2 = multiple ? new MultiSelect2() : new SingleSelect2();
Better use true/false variable value than "multiple"/undefined in this condition.

Tested in Opera 12 and IE 8.0.7601
fix initSelection with empty input value
Czech translation

Czech translation with inflection function from David Vallner (author
of Slovak translation)
Merge pull request #1092 from michalmarek/master

Czech translation
Fix for random scrolling when using hierarchical data

When using hierarchical data there is a random scroll jump when hovering over select options. The reason is that in the case of hierarchical data the highlightable choices are <ul> and thus their outer height is many pixels (includes the children's height as well). A fix is to make the height calculations by using the the label divs.
remove debug statement
Merge pull request #1095 from nolamesa/patch-1

Fix for random scrolling when using hierarchical data
Add Polish translation
Merge pull request #1101 from jkondratowicz/master

Add Polish translation
Add link to Yii integration. Closes #1102
Fix focus issue on multi-value select

Inside the multi-value select box, when you hit backspace next to the
choice, it gets the `select2-search-choice-focus` class, but that class
is not being removed when select box loses the focus.
Merge pull request #1111 from lazyhammer/fix-choice-focus

Fix focus issue on multi-value select (closes #1109)
Useless space removed.
Merge pull request #1123 from sineld/patch-1

Useless space removed.
Fix: Incorrect Bower specification

 - ~ version means 1.4.x, not >= 1.4 which is what we want
 - there is no spinner.gif, but there is a select2-spinner.gif
Merge pull request #1127 from Iristyle/patch-1

Fix: Incorrect Bower specification
merging the hebrew locale commit from KingYes
Add Japanese translation